The present invention generally relates to devices and methods to treat an eye of a patient, and more specifically to intraocular implants that provide extended release of a therapeutic agent to an eye in which the implant is placed.
Steroids, such as the corticosteroid, fluocinolone acetonide (1,4-pregnadien-6α, 9α-difluoro-11β,16α,17,21-tetrol-3,20-dione 16,17-acetonide), are usually given topically, systemically, or periocularly, as an injection, to treat uveitis. All three methods of delivery have drawbacks, e.g., topical corticosteroids do not treat diseases in the back on the eye, systemic corticosteroids are often associated with many unwanted side effects, and periocular injections may sometimes cause globe perforation, periocular fibrosis and ptosis.
An alternative that may circumvent the drawbacks of the above-mentioned delivery methods is to use sustained-released drug delivery systems. In 2000, Jaffe et al. reported using compressed pure fluocinolone acetonide pellets coated with silicone and polyvinyl alcohol as a fluocinolone sustained delivery device (Jaffe, G. J. et al., Journal of Ophthalmology and Vision Surgery, Vol 41, No. 11, October 2000). They obtained release rates of 1.9±0.25 μg/day (6 months) and 2.2±0.6 μg/day (45 days) for the 2-mg device and 15-mg device, respectively. The duration of release for the 2-mg and 15-mg device was estimated to be 2.7 and 18.6 years, respectively. U.S. Pat. Nos. 6,217,895 and 6,548,078 disclose sustained release implants for delivering a corticosteroid, such as fluocinolone acetonide, to an eye. However, fluocinolone acetonide intravitreal implants made by Control Delivery Systems (the assignee of U.S. Pat. Nos. 6,217,895 and 6,548,078) were only partially successful and led to the development of cataracts and increased intraocular pressure.
In addition, intravitreal injection of triamcinolone acetonide (KENALOG®) for treatments of non-infectious uveitis, and macular edema due to various retinal diseases has appeared to be safe and effective.
Additional biocompatible implants for placement in the eye have been disclosed in a number of patents, such as U.S. Pat. Nos. 4,521,210; 4,853,224; 4,997,652; 5,164,188; 5,443,505; 5,501,856; 5,766,242; 5,824,072; 5,869,079; 6,074,661; 6,331,313; 6,369,116; and 6,699,493.
It would be advantageous to provide eye implantable drug delivery systems, such as intraocular implants, and methods of using such systems, that are capable of releasing a therapeutic agent at a sustained or controlled rate for extended periods of time and in amounts with few or no negative side effects.